Synthesis and structure of new mononuclear octahedral cobalt(III) dioximates derived from isonicotinic hydrazide

Article abstract of DOI:10.1016/j.molstruc.2014.01.084

New organic ligand L (1) resulting from isonicotinic hydrazide and 2,4-pentanedione has been prepared and investigated by physicochemical methods, including elemental analysis, ¹H and ¹³C NMR, IR spectroscopy and X-ray studies. The X-ray investigation revealed that the condensation of 2,4-pentanedione with isonicotinic hydrazide is accompanied by the formation of a five-membered ring including three carbon atoms of 2,4-pentanedione and two nitrogen atoms of the isonicotinic hydrazide fragment. The reaction between [Co(DfgH)₂Br(H₂O)] (DfgH₂ = diphenylglyoxime) and L resulted in the formation of the mononuclear octahedral complex [Co(DfgH)₂BrL] (2) with the substitution of the water molecule in the apical position by the ligand L. The reaction starting from [Co(DmgH)₂Cl(H₂O)] (DmgH = dimethylglyoxime) and L resulted in the mononuclear octahedral Co(III) complex with the composition [Co(DmgH)₂ClL′] (3), where L′ unexpectedly represents a dehydrated derivative of L. The two coordination compounds are characterized by X-ray diffraction method. The IR, ¹H NMR spectral studies of new compounds are also reported.

Full text of DOI:10.1016/j.molstruc.2014.01.084

Journal of Molecular Structure 1063 (2014) 274–282
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Synthesis and structure of new mononuclear octahedral cobalt(III)
dioximates derived from isonicotinic hydrazide
Maria Cocu a, Ion Bulhac a, Eduard Coropceanu a, Elena Melnic b, Sergiu Shova a,b, Olga Ciobanica a,
Victoria Gutium a, Paulina Bourosh b,
⇑
a Institute of Chemistry, Academy of Sciences of Moldova, Academiei str. 3, MD2028 Chisinau, Republic of Moldova
b Institute of Applied Physics, Academy of Sciences of Moldova, Academiei str. 5, MD2028 Chisinau, Republic of Moldova
h i g h l i g h t s
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
New Schiff base resulting from isonicotinic hydrazide and 2,4-pentanedione.
Compounds comprise novel ligand and its dehydrated derivative.
Mononuclear octahedral complex [Co(DfgH)2BrL] with the substitution of the water molecule by new ligand.
Co(III) complex [Co(DmgH)2ClL0], where L0 represents a dehydrated derivative of L.
The crystal structures were studied.
a r t i c l e i n f o
a b s t r a c t
Article history:
New organic ligand L (1) resulting from isonicotinic hydrazide and 2,4-pentanedione has been prepared
and investigated by physicochemical methods, including elemental analysis, 1H and 13C NMR, IR
spectroscopy and X-ray studies.
The X-ray investigation revealed that the condensation of 2,4-pentanedione with isonicotinic hydra-
zide is accompanied by the formation of a five-membered ring including three carbon atoms of 2,4-pen-
tanedione and two nitrogen atoms of the isonicotinic hydrazide fragment.
The reaction between [Co(DfgH)2Br(H2O)] (DfgH2 = diphenylglyoxime) and L resulted in the formation
of the mononuclear octahedral complex [Co(DfgH)2BrL] (2) with the substitution of the water molecule in
the apical position by the ligand L. The reaction starting from [Co(DmgH)2Cl(H2O)] (DmgH = dim-
ethylglyoxime) and L resulted in the mononuclear octahedral Co(III) complex with the composition
[Co(DmgH)2ClL0] (3), where L0 unexpectedly represents a dehydrated derivative of L. The two coordina-
tion compounds are characterized by X-ray diffraction method. The IR, 1H NMR spectral studies of new
compounds are also reported.
Received 30 September 2013
Received in revised form 28 January 2014
Accepted 28 January 2014
Available online 4 February 2014
Keywords:
Cobalt(III) dioximates
New Schiff base
Isonicotinic hydrazide
Crystal structures
Ó 2014 Elsevier B.V. All rights reserved.
1. Introduction
of biological activity, such as antibacterial and antiviral activities;
some of them have already been used in medical practice. Deriva-
The Schiff bases and their metal complexes have been used in
various biological systems, as polymers and dyes, and as antifertil-
ity and enzymatic agents [1]. These Schiff base metal derivatives
are of considerable interest, because they are used as model com-
plexes for biological systems and thus contribute to the knowledge
of their structure and behavior [2].
Recently, isonicotinic hydrazide and its derivatives have been
the subject of interest to researchers of different profiles. Many
of these ligands and their complexes have shown a wide spectrum
tives of isonicotinic acid and its hydrazide (INH) are well known for
their highly specific antituberculous activity.
An important role in chemistry of biologically active com-
pounds is played by transition metal dioximates. The complexation
ability of -dioximes with d-metals attracts researchers not only for
synthesis models of vitamin B12 [3], but also for a wide range of
synthetic, analytical, and structural possibilities. Studies to obtain
new materials based on transition metal complexes with a porous
structure, such as biocatalysts [4,5], are carried out to synthesize
coordination compounds with new composition, structure, and
properties. Coordination compounds with dioximes as ligands
can be mono-, di- or polynuclear [3,4,6].
⇑
Corresponding author. Tel.: +373 22 73 81 54; fax: +373 22 72 58 87.
E-mail address: bourosh.xray@phys.asm.md (P. Bourosh).
http://dx.doi.org/10.1016/j.molstruc.2014.01.084
0022-2860/Ó 2014 Elsevier B.V. All rights reserved.

M. Cocu et al. / Journal of Molecular Structure 1063 (2014) 274–282
275
Using the building blocks in the preparation of the coordination
compounds, allows the assembly of complex molecules, which by
straightforward pathway synthesis is more difficult. Bis-dioxime
blocks of synthesis with a water molecule in axial position, due
to its liability are a successful start point for obtaining new mate-
rials, through substitution by various ligands. Often the relative lia-
bility of such group may be a major drawback to the use of this
method [7].
The introduction of various organic molecules in metal com-
plexes as ligands can significantly change their properties.
In this paper we describe the synthesis and properties of
L = 2,4-pentanedione isonicotinoyl hydrazone (1) and its complexes
with dioximates of a trivalent Co metal ion: [Co(DfgH)2BrL] (2) and
[Co(DmgH)2ClL0] (3), where DfgH2 = diphenylglyoxime, DmgH =
dimethylglyoxime and L0 represents the dehydrated derivative of L.
spectrometer in Vaseline in the range of 4000–400 cmꢁ1 and ATR in
the range of 4000–650 cmꢁ1. Melting points were measured in a
Boethius melting point apparatus and were uncorrected.
2.4. Crystal data for 1–3
Crystal dimensions for 1–3 are 0.30 ꢂ 0.10 ꢂ 0.10 mm,
0.20 ꢂ 0.15 ꢂ 0.10 mm and 0.25 ꢂ 0.10 ꢂ 0.10 mm respectively.
Experimental data for 1 and 2 were collected on an Xcalibur CCD
-axis diffractometer and a graphite monochromator using Mo K
radiation. Experimental data for 3 were collected on a Nonius Kap-
pa CCD diffractometer with graphite monochromated Mo K radi-
a
a
ation. Frames for 3 were integrated and corrected for Lorentz and
polarization effects using DENZO [8]. The scaling, as well as the
global refinement of crystal parameters, was performed by SCALE-
PACK [8]. The absorption correction was introduced by a semi-
empirical method from symmetry equivalent reflections [9]. Final
unit cell dimensions for 1–3 were obtained and refined on an entire
data set. All calculations necessary to solve the structures and to re-
fine the proposed model were carried out with the SHELX program
[10]. The non-hydrogen atoms were treated anisotropically (full-
matrix least squares method on F2). The carbon bounded H atoms
were placed in calculated positions and were treated using a riding
model approximations with Uiso(H) = 1.2Ueq(C), while the oxygen
bounded H-atoms were found from differential Fourier maps at
an intermediate stage of the refinement, and their positions were
constrained using the AFIX 83 instruction in SHELX for oxime and
hydroxyl groups. These hydrogen atoms were refined with the iso-
tropic displacement parameter Uiso(H) = 1.5Ueq(O). The X-ray data
and the details of the refinement for 1–3 are summarized in Table 1,
the selected geometric parameters are presented in Table 2, and
hydrogen-bonding geometry is given in Table 3.
2. Experimental
2.1. Chemicals
All chemicals were of reagent grade and used as purchased
without further purification.
2.2. Syntheses of ligand and complexes
2.2.1. Preparation of the Schiff base L (1)
2,4-pentanedione isonicotinoylhydrazone (L) was prepared by
reacting isonicotinic hydrazide (0.012 mol, 1.5 g) dissolved in
7 ml of C2H5OH with 2,4-pentanedione (0.045 mol, 1.1 ml) in 1:1
molar ratio. The reaction mixture was heated at 65 °C for 15 min.
White crystals formed after 4 days. The crystals were separated
by filtration, washed with ethanol and diethyl ether. Yield 1.16 g,
50%, m.p. 131–133 °C. Anal. Found: C, 60.30; H, 5.80; N, 18.92. Calc.
for C11H13N3O2 (fw 219.09): C, 60.20; H, 5.90; N, 19.17.
1H and 13C NMR spectra for L: (400 MHz, CDCl3), d = 1.89 (s, 6H,
CH3), 2.83–3.01 (d, 2H, CH2), 6.66 (s, 1H, OH) and 7.58–8.63 ppm
(d, 4H, Py). (400 MHz, CDCl3): d = 16.305 (C, CH3), 26.249
(C, CH3), 52.342 (C, CH2), 91.799 (C, >C@N), 122.910 (2C, Py),
144.267 (C, >C<), 149.905 (2C, Py), 156.675 (C, >CAOH), 164.849
(C, >C@O).
3. Results and discussion
Condensation of isonicotinic hydrazide and 2,4-pentanedione in
a molar ratio of 1: 1 resulted in the formation of a novel V-shaped
organic ligand L (1) that consists of two cycles, the six-membered
pyridine, and the five-membered hydroxyl-and-dimethyl-substi-
tuted diazole one joined via a carbonyl bridge (Scheme 1). An anal-
ogous cyclization was observed for the formation of pyrazoles by
condensation of various 1,3-diketones and hydrazines, acylhydra-
zines or sulfonyl hydrazines, described in [11].
During the condensation, one azomethine C@N bond and CAN
bonds between each carbonyl groups of 2,4-pentanedione and
isonicotinic hydrazide NH2A and ANHA group were formed. One
water molecule saturated the double bond ACH@C(CH3)A of
2,4-pentanedione fragment, so the addition of one hydroxyl group
at the carbon atom >C(CH3)A took place. The ligand was isolated as
air-stable white needle-like crystals which are soluble in chloro-
form, DMF, dimethylsulfoxide, ethanol, and methanol, and low
soluble in water, hexane, and diethyl ether (melting point 131–
133 °C).
2.2.2. Preparation of the complexes
[Co(DfgH)2BrL] (2) was prepared by reacting [Co(DfgH)2Br(H2-
O)] (0.001 mol, 0.64 g) dissolved under heating in 30 ml of a
CH3OH:H2O mixture (1:1) with L (0.001 mol, 0.23 g) dissolved in
20 ml CH3OH. The resulting mixture was heated at 70 °C for
10 min, and then the brown solution was filtered and left for slow
evaporation at room temperature. The brown needle-like crystals
were separated by filtration. Yield: 0.46 g, 55%. Anal. Found: Co,
6.84; C, 55.67; H, 4.05; N, 11.61. Calc. for C39H35N7O6CoBr (fw
836.26): Co, 7.04; C, 55.99; H, 4.21; N, 11.72.
[Co(DmgH)2ClL0]
(3)
was
prepared
by
reacting
[Co(DmgH)2Cl(H2O)] (0.001 mol, 0.34 g) dissolved under heating
in 20 ml of a mixture of CH3OH:H2O (1:1) with L (0.001 mol,
0.23 g) dissolved in 20 ml of CH3OH. The resulting mixture was
heated at 80 °C for 10 min, then filtered and left for slow evapora-
tion at room temperature. The brown prismatic crystals were sep-
arated by filtration. Yield: 0.32 g, 40%. Anal. Found: Co, 10.64; C,
41.62; H, 4.86; N, 17.92. Calc. for C19H27N7O6CoCl (fw 801.38):
Co, 10.83; C, 41.96; H, 5.0; N, 18.03.
The product was characterized using elemental analysis, IR
spectroscopy, and 1H and 13C NMR spectroscopy, which confirmed
the formation of a cycle composed of five atoms: three carbon
atoms of acetylacetone and two nitrogen atoms of the isonicotinic
hydrazide fragment, which is in agreement with the formulas in
Scheme 1.
New
mononuclear
octahedral
cobalt(III)
complexes
[Co(DfgH)2BrL] (2) (Fig. 2) and [Co(DmgH)2ClL0] (3) (Fig. 3)
have been synthesized by interaction of previously
obtained [Co(DfgH)2Br(H2O)] (DfgH2 = diphenylglyoxime) or
[Co(DmgH)2Cl(H2O)] (DmgH2 = dimethylglyoxime) [7] with
2,4-pentanedione isonicotinoylhydrazone (1) in a basic methano-
2.3. Analyses and physical measurements
Elemental analyses were performed by standard micro methods.
The IR spectra were obtained on a FT IR Spectrum-100 Perkin–Elmer

276
M. Cocu et al. / Journal of Molecular Structure 1063 (2014) 274–282
Table 1
Crystal data and structure refinement parameters for 1–3.
1
2
3
Empirical formula
Formula weight
Temperature (K)
Crystal system
Space group
Z
C
11H13N3O2
C39H35Br1Co1N7O6
C19H25Cl1Co1N7O5
525.84
100(2)
Monoclinic
P21/a
4
219.24
293(2)
Orthorhombic
Pbca
836.58
293(2)
Triclinic
P ꢁ 1
2
8
Unit cell dimensions
a (Å)
b (Å)
c (Å)
10.8965(8)
13.2845(8)
15.2176(9)
90
90
90
2202.8(2)
1.322
0.094
928
6355/2047
1582
11.4105(9)
14.3341(10)
14.4005(11)
109.116(7)
111.750(7)
99.581(6)
1952.7(3)
1.423
1.517
856
9994/7219
2819
13.6760(3)
10.9670(4)
15.0540(5)
90
99.8240(9)
90
2224.8(1)
1.570
0.939
a
(°)
b (°)
(°)
Cell volume (Å3)
Dcalc (g cmꢁ3
(mmꢁ1
F (000)
Reflections collected/unique
c
)
l
)
1088
14,417/4128
3834
Reflections with (I>2r(I))
Parameters
145
487
289
R1, wR2[I>2
R1, wR2(all data)
r
(I)]
0.0415, 0.1247
0.0541, 0.1297
0.0402, 0.0702
0.1316, 0.0939
0.0436, 0.1104
0.0475, 0.1130
lic medium under heating, L0 unexpectedly represents a dehy-
drated derivative of L .
435 cmꢁ1 characteristic of
ms(CoAN) bond. The band at
1563 cmꢁ1 can be attributed to the stretching vibrations of C@C
bonds of the aromatic fragment and the band with medium inten-
sity at 1711 cmꢁ1 to the ketone group. The bands at 1423 and
1381 cmꢁ1 correspond to bending vibrations of the methyl groups.
In complexes 2 and 3, the water molecule from the apical posi-
tion was substituted by L/L0 ligands (Scheme 2).
Complexes were isolated as air-stable brown needle-like crys-
tals for 2 and brown prisms for 3. They are soluble in DMF and
DMSO, less soluble in water and insoluble in ethanol and metha-
nol. The complexes are neutral with the metal charge entirely
neutralized by the Brꢁ and Clꢁ anions. In each case, the products
were characterized using IR spectroscopy and elemental analysis.
Complexes 2 and 3 were also analyzed by 1H and 13C NMR spec-
troscopy. The structure of compounds 1–3 was determined using
X-ray analysis.
3.2. 1H and 13C NMR spectra
The 1H NMR and 13C NMR spectra of L in CDCl3 solutions
showed the presence of all atoms of hydrogen and carbon pre-
dicted by molecular formula 1 (Fig. 1).
In the 1H NMR spectra of L solution in CDCl3, eight groups of sig-
nals were recorded, which were attributed to protons of two CH3
groups d = 2.83–3.01 (d) ppm, one OH group d = 1.89 (s) ppm,
one CH2 group d = 6.66 (s) ppm and four signals of hydrogen atoms
of the pyridine cycle belonging to d = 7.58–8.63 ppm.
3.1. Infrared spectra
The 13C NMR spectra data (DEPT135, HMBC, HMQC) of L solu-
tion in CDCl3 indicate the presence of 11 carbon atoms at
d = 16.305 (C, CH3), 26.249 (C, CH3), 52.342 (C, CH2), 91.799 (C,
>C@N), 122.910 (2C, Py), 144.267 (C, >C<), 149.905 (2C, Py),
156.675 (C, >CAOH), 164.849 (C, >C@O).
The IR spectrum of isonicotinic hydrazide exhibits amide group
frequencies at 1660, 1550, and 1220 cmꢁ1. In the IR spectrum of L
(1), a strong band at 1623 cmꢁ1 is observed, which may be as-
signed to (C@O) of the isonicotinic group stretching vibrations,
and three bands at 3110, 2972, and 1314 cmꢁ1 assignable to the
In the 1H NMR spectrum of complex 2 the following data may
be assigned to signals of ligand L: 1.83 ppm (CH3), 2.81–3.01 ppm
(CH2), 6.79 ppm (OH), 7.76, 8.42 ppm (pyridine ring). The signals
at 7.14–7.39 ppm indicate the presence of diphenylglyoxime ben-
zene rings.
aliphatic hydrogen-bonded OH group
(CAO), respectively. The band at 1330 cmꢁ1 may be assigned to
the bending vibrations of the NH group. The bands at 1407 and
m (OH), m(@CAH) and
m
1443 cmꢁ1 can be attributed to vibrations
m(CH2) and m(C@C),
respectively. The absence of bands at 3150–3400 cmꢁ1 in the IR
spectrum of L indicates that the NH2 group reacts with the
aldehyde.
In the 1H NMR spectrum for 3, the signal from 2.34 ppm is as-
signed to the methyl groups and is slightly shifted compared to
the uncoordinated ligand field. The signal at 18.44 ppm corre-
sponds to protons of the OH oxime groups and indicates the forma-
tion of hydrogen bonds between the two monoanions of dioxime.
The IR spectrum of 2 contains a band at 3675 cmꢁ1 attributable
to the stretching vibrations of the free OAH bond. The bands at
2988, 2972, and 2901 cmꢁ1 can be attributed to vibrations
m
s(CH2),
as(CH3). The presence of the dioximic ligands proven
(C@N)oxime at 1630, (NO) at 1289 and 1134, (OH)
(CNO) at 736, mas (CoAN) at 509 and ms(CoAN) at
m
s(CH3) and
by the bands
at 967,
m
m
m
c
3.3. Description of structures
m
440 cmꢁ1. The bands in the region 1443 and 1378 cmꢁ1 are attrib-
The CSD [12] revealed the structure of only one related com-
pound, 5-hydroxy-3-methyl-5-phenyl-4,5-dihydro-1H-pyrazol-1-l
[13], which has been synthesized by addition of isoniazide to a
solution of benzoylacetone. In addition to this compound in CSD
[12] there are structures of two derivatives of pyrazol-1-yl)
(pyridinyl) methanone [14,15] and structures of two ferrocenyl
compounds containing ligands of this class [16,17]. Single crystal
uted to vibrations of d(CH3). Aromatic ring vibrations are charac-
terized by the bands at 1486, 1027, and 892 cmꢁ1
.
The IR spectrum of complex 3 shows the absorption of the mon-
odeprotonated DmgH ligand in the region of 1646 cmꢁ1, which can
be attributed to the
m
(C@N)oxim group, at 1241 of
m
(NO)ionizate and
1090 cmꢁ1 of
m(OH)DH, 724 of d(CNO), 513 of
mas(CoAN) and

M. Cocu et al. / Journal of Molecular Structure 1063 (2014) 274–282
277
Table 2
Table 2 (continued)
Selected bond distances and angles for 1-3.
1
2
3
1
2
3
O(1)AC(6)AN(2)
120.7(1)
118.3(1)
121.0(1)
99.9(1)
110.9(1)
113.2(1)
110.5(1)
113.0(1)
108.6(1)
104.6(1)
122.9(1)
114.8(1)
122.3(1)
–
122.6(5)
119.5(5)
117.8(5)
99.7(4)
123.8(3)
122.1(3)
114.1(3)
105.5(3)
123.4(3)
130.8(3)
–
Co(1)AN(1)
Co(1)AN(4)
Co(1)AN(5)
Co(1)AN(6)
Co(1)AN(7)
Co(1)ABr(1)/Cl(1)
O(1)AC(6)
O(2)AC(7)
N(1)AC(1)
N(1)AC(5)
N(2)AN(3)
N(2)AC(6)
N(2)AC(7)
N(3)AC(9)
O(3)AN(4)
O(4)AN(5)
O(5)AN(6)
O(6)AN(7)
N(4)AC(12)
N(5)AC(13)
N(6)AC(14)
N(7)AC(15)
C(1)AC(2)
C(2)AC(3)
C(3)AC(4)
C(3)AC(6)
C(4)AC(5)
C(7)AC(8)
C(7)AC(11)
C(8)AC(9)
C(9)AC(10)
C(12)AC(13)
C(14)AC(15)
–
–
–
–
–
–
1.980(4)
1.967(2)
1.904(2)
1.918(2)
1.883(2)
1.889(2)
2.2318(7)
1.204(4)
–
O(1)AC(6)AC(3)
N(2)AC(6)AC(3)
N(2)AC(7)AC(8)
N(2)AC(7)AC(11)
C(11)AC(7)AC(8)
O(2)AC(7)AN(2)
O(2)AC(7)AC(11)
O(2)AC(7)AC(8)
C(9)AC(8)AC(7)
C(8)AC(9)AC(10)
N(3)AC(9)AC(8)
N(3)AC(9)AC(10)
N(4)AC(12)AC(13)
N(5)AC(13)AC(12)
N(6)AC(14)AC(15)
N(7)AC(15)AC(14)
1.880(4)
1.897(4)
1.890(4)
1.891(4)
2.3792(9)
1.224(5)
1.392(7)
1.342(5)
1.325(5)
1.406(5)
1.326(6)
1.502(6)
1.271(6)
1.338(5)
1.333(4)
1.336(4)
1.330(4)
1.308(6)
1.305(5)
1.304(5)
1.295(5)
1.375(6)
1.378(6)
1.386(6)
1.506(6)
1.380(6)
1.518(7)
1.504(8)
1.477(7)
1.488(7)
1.466(6)
1.469(6)
111.3(5)
114.3(6)
108.6(5)
113.0(5)
109.0(6)
105.0(5)
124.6(5)
113.9(5)
121.4(5)
113.4(4)
111.4(4)
113.5(3)
112.7(4)
1.228(2)
1.396(2)
1.330(2)
1.327(2)
1.398(2)
1.352(2)
1.507(2)
1.278(2)
–
–
–
–
–
–
–
1.350(4)
1.351(4)
1.389(4)
1.382(4)
1.403(4)
1.321(4)
1.352(3)
1.354(3)
1.335(3)
1.336(3)
1.290(3)
1.296(3)
1.301(4)
1.302(4)
1.387(4)
1.383(4)
1.386(4)
1.511(4)
1.381(4)
1.362(5)
1.484(5)
1.415(4)
1.493(4)
1.472(4)
1.469(5)
107.0(3)
128.3(3)
111.6(3)
120.3(3)
112.5(2)
112.6(2)
113.6(2)
112.5(3)
–
–
–
X-ray structure study of compound 1 established that it differs
from the nearest compound [13] by the substituent at position 5
of the pyrazole. (5-Hydroxy-3,5-dimethyl-4,5-dihydro-1H-pyra-
zol-1-yl)(pyridin-4-yl)methanone 1 is a chiral molecule which
contain two heterocyclic rings (Fig. 1).
–
–
–
1.384(2)
1.386(2)
1.389(2)
1.509(2)
1.375(2)
1.533(2)
1.508(2)
1.476(2)
1.484(2)
–
The dihedral angle between the mean planes of the pyrazole
and pyridine rings equals to 29.6°. The five-membered ring is al-
most planar ( 0.018 Å), with the C(10) atom whose deviation does
not exceed ꢁ0.015 Å, and the deviations of the O(2) and C(11)
atoms from this plane are 1.151 and ꢁ1.269 Å. This structure
provides a -coupling between the aromatic system and other frag-
ments of the molecule, although the interatomic distance between
C(3) and C(6) atoms is not greatly reduced (1.509(2) Å). The X-ray
investigation revealed that formation of L is the result of condensa-
tion of 2,4-pentanedione with isonicotinic hydrazide. The same
form is found in [13], in which the values of interatomic distances
N(2)AN(3), N(2)AC(7), N(3)AC(9), C(7)AC(8), and C(8)AC(9) are
1.408, 1.501, 1.270, 1.537, and 1.483 Å according to the numbering
in Fig. 1. However, in [13] the dihedral angle of the mean plane of
the pyrazole ring with the pyridine ring equals to 45.0°, and the
deviation of the atoms from mean plane of the five-membered ring
is 0.047 Å, while C(10) atom is slightly deviated from the plane
(ꢁ0.058 Å), and the deviations of the O(2) and C(11) atoms are
ꢁ1.267 and 1.095 Å. The interatomic distances C(6)AO(1) in 1
and in (5-hydroxy-3-methyl-5-phenyl-4,5-dihydro-1H-pyrazol-1-
yl)(pyridin-4-yl)methanone monohydrate [13] are 1.228(2) and
1.229 Å, respectively, and indicate in favor of double bond, and
the values found for C(6)AN(2) and C(6)AC(3) (1.352(2), 1.509(2)
in 1 and 1.345, 1.502 Å in [13]) are also slightly different. In this
case, at the C(6) atom, a slight difference was observed in both
the valence angles N(2)C(6)C(3)–121.0(1) in 1 and 119.8° in [13]
and torsion angles C(6)N(2)C(7)O(2) 64.1(1) in 1 and 64.9° in
5-(5-hydroxy-3-methyl-1-(4-pyridylcarbonyl)-5-trifluoromethyl-
2(Z)-pyrazoline-4-ylidenehydrazino)-1H-4-(ethoxycarbonyl)pyra-
zole [14] and C(6)N(2)C(7)C(11) –62.0(1) in 1 and 56.7° in [13].
Therefore, it was revealed that there are steric hindrances deter-
mined by the formation of a rigid intramolecular hydrogen bond
O(2)AHꢃ ꢃ ꢃO(1) (Table 3) in [13].
–
N(1)ACo(1)ABr(1)/Cl(1)
N(4)ACo(1)AN(1)
N(4)ACo(1)AN(5)
N(4)ACo(1)AN(6)
N(4)ACo(1)AN(7)
N(4)ACo(1)ABr(1)/Cl(1)
N(5)ACo(1)AN(1)
N(5)ACo(1)AN(6)
N(5)ACo(1)AN(7)
N(5)ACo(1)ABr(1)/Cl(1)
N(6)ACo(1)AN(1)
N(6)ACo(1)ABr(1)/Cl(1)
N(7)ACo(1)AN(1)
N(7)ACo(1)AN(6)
N(7)ACo(1)ABr(1)/Cl(1)
C(1)AN(1)AC(5)
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
178.4(1)
92.3(2)
81.5(2)
176.8(2)
98.3(2)
89.0(1)
91.1(2)
98.8(2)
179.8(2)
90.1(1)
91.0(2)
176.91(6)
92.29(9)
80.25(9)
178.25(90)
98.45(10)
90.80(7)
92.10(9)
98.69(10)
177.52(9)
88.41(7)
89.14(9)
87.77(7)
90.06(9)
82.55(10)
89.50(7)
118.3(2)
121.3(2)
120.3(2)
118.3(2)
130.7(3)
111.0(2)
104.9(2)
119.1(2)
123.1(2)
117.7(2)
119.5(2)
123.4(2)
116.9(2)
122.5(2)
122.0(2)
115.4(2)
122.1(2)
122.0(2)
115.9(2)
122.4(3)
119.0(3)
119.1(3)
122.2(3)
118.7(3)
119.1(3)
122.3(3)
87.8(1)
88.9(2)
81.04(2)
89.9(1)
116.3(1)
–
–
122.9(1)
124.3(1)
112.8(1)
107.9(1)
–
–
–
–
–
–
–
–
117.9(4)
121.4(3)
120.6(3)
121.4(4)
125.5(4)
112.0(4)
108.1(4)
120.5(4)
123.0(3)
116.4(3)
121.3(4)
121.6(3)
117.0(3)
121.3(4)
122.1(3)
116.6(3)
121.5(3)
121.7(3)
116.8(3)
122.0(4)
120.2(4)
117.6(5)
119.7(5)
122.5(5)
119.0(4)
123.3(4)
Co(1)AN(1)AC(1)
Co(1)AN(1)AC(5)
C(6)AN(2)AN(3)
C(6)AN(2)AC(7)
N(3)AN(2)AC(7)
N(2)AN(3)AC(9)
O(3)AN(4)AC(12)
Co(1)AN(4)AO(3)
Co(1)AN(4)AC(12)
O(4)AN(5)AC(13)
Co(1)AN(5)AO(4)
Co(1)AN(5)AC(13)
O(5)AN(6)AC(14)
Co(1)AN(6)AO(5)
Co(1)AN(6)AC(14)
O(6)AN(7)AC(15)
Co(1)AN(7)AO(6)
Co(1)AN(7)AC(15)
N(1)AC(1)AC(2)
–
–
–
–
Thus, geometry of 1 (Fig. 1) does not differ from that found in
[2], but a similar V-shaped conformation of the ligand during com-
plexation, provides its coordination to transition metal ions in both
monodentate and chelate modes with the formation of metallocy-
cles or executing a bridging function, using donor atoms N(1), N(3),
O(1) and O(2). It is known that derivatives of pyridinecarboxylic
acids, which have, along with the nitrogen atom of the pyridine
ring, other donor groups, reveal the different coordination modes
to the metal depending on the environment, the nature of the com-
plexating metal, and competing ligands.
124.5(2)
118.6(2)
117.1(1)
126.3(1)
116.2(1)
119.7(2)
123.8(2)
C(1)AC(2)AC(3)
C(2)AC(3)AC(4)
C(2)AC(3)AC(6)
C(4)AC(3)AC(6)
C(5)AC(4)AC(3)
N(1)AC(5)AC(4)

278
M. Cocu et al. / Journal of Molecular Structure 1063 (2014) 274–282
Table 3
Hydrogen bond distances (Å) and angles (°) for 1–3.
DAH. . .
A
d(DAH)
d(H. . .A)
d(D. . .A)
(DHA)
Symmetry transformation for acceptor
1
O(2)AH(2A)ꢃ ꢃ ꢃO(1)
0.82
0.82
2.57
2.14
3.043(2)
2.860(2)
118
146
x, y, z
ꢁx + 1/2, ꢁy, z + 1/2
O(2)AH(2A)ꢃ ꢃ ꢃN(1)
2
O(2)AH(2A)ꢃ ꢃ ꢃO(1)
O(4)AH(4)ꢃ ꢃ ꢃO(5)
O(6)AH(6)ꢃ ꢃ ꢃO(3)
0.82
0.82
0.82
1.99
1.68
1.67
2.800(5)
2.474(4)
2.465(4)
168
164
164
ꢁx + 1, ꢁy + 1, ꢁz ꢁ 1
x, y, z
x, y, z
3
O(3)AH(3A)ꢃ ꢃ ꢃO(6)
0.82
0.82
1.70
1.73
2.489(3)
2.514(3)
161
160
x, y, z
x, y, z
O(4)AH(4A)ꢃ ꢃ ꢃO(5)
In the formation of the crystal structure it is important zig–zag
chains generation along the c axis in which the main one is the
hydrogen bond O(2)AHꢃ ꢃ ꢃN(1) (ꢁx + 1/2, ꢁy, z + 1/2), O(2)ꢃꢃꢃN(1)
2.860(2) Å (Table 3 and Fig. 2). The structure also provided a weak
hydrogen bond which stabilizes this chain and a weaker hydrogen
bond C(8)AH(1)ꢃ ꢃ ꢃO(1) (ꢁx + 1/2, y + 1/2, z) (C(8)ꢃ ꢃ ꢃO(1)
3.526(5) Å) which is responsible for the binding of these chains
into layers along the crystallographic a axis.
Scheme 1. Mode of formation V-shaped organic ligand L (1).
The asymmetric units of 2 and 3 comprise halogen dioximates
of Co(III) with L and L0 (Figs. 3 and 4). The structures of molecular
complexes 2 and 3 fall into the Chugaev’s class of compounds [21]
with the general formula [MX(DioxH)2A], where M is Co(III) ion,
In addition, on the basis of the CSD study [12], it was revealed
that this type of ligands coordinate to the metal ion mainly via the
nitrogen atom of the heterocycle. In catena-(bis(
mide)-(phthalato)-di-silver(I) trihydrate) complex [18] the isonic-
otinamide ligand coordinates by N, donor atoms to two
different metal atoms as a bridging linker, but in the Mn(II) com-
plex catena-(bis( 2-isonicotinehydrazido)-(isonicotinehydrazido)-
triaquachloro-di-manganese trichloride isonicotinehydrazide
l2-isonicotina-
DioxHꢁ is the charged residue of
a
-dioxime (dimethylglioximate-
O
ion DmgHꢁ, 1,2-cyclohexanedionedioximate ion NioxHꢁ or
a-ben-
zyldioximate ion DfgHꢁ), A is a neutral molecule derived from
isonicotinic hydrazide (L or L’), X is the monoanion Brꢁ or Clꢁ.
The structure of Cu(II) dimethylglyoximate with isonicotina-
l
solvate) [19] it coordinates through the isonicotinehydrazido set
of O,N,N atoms and 2-pyridine-2-carbaldehyde(isonicotinoyl)
hydrazone) in the bis(l2-pyridine-2-carbaldehyde(isonicotinoyl)
hydrazone)-hexachlorotetrakis(dimethylsulfoxide)-tri-manga-
nese(II) complex [20]. Involvement in the coordination through
two atoms resulting in a five-membered metallocycle is ensured
by different rotations around single bonds. But, in most cases,
the isonicotinamide derivatives coordinate in a monodentate
mode via the nitrogen atom of the heterocycle.
mide
with
[Cu(DmgH)2(Inia)]
nicotinamide and ethyl ester of isonicotinic acid
[22],
Fe(II)
a-benzildioximates
[Fe(DfgH)2(3-CONH2-Py)2] and [Fe(DfgH)2(4-COOC2H5-Py)2] [23],
dimethylglyoximates and 1,2-cyclohexanedionedioximates Co(II)
and Co(III) with isonicotinamide [CoII(DmgH)2(Inia)2], [CoIII(-
DmgH)2
(Inia)2][PF6], [CoIII(NioxH)2(Inia)2][PF6] and [CoIIICl(DmgH)2(Inia)]
Inia-isonicotinamide [24] and dimethylglyoximates Co(III) with
Scheme 2. Synthesis of complexes 2 and 3.

M. Cocu et al. / Journal of Molecular Structure 1063 (2014) 274–282
279
Fig. 1. ORTEP drawing for new organic molecule 1 with a numbering scheme.
Thermal ellipsoids are shown at a 50% probability level.
isonicotinic acid (Ina) [CoIIICl(DmgH)2(Ina)] were previously de-
scribed [25,26].
Fig. 3. ORTEP drawing for 2 with a numbering scheme and the shortest intramo-
lecular OꢃꢃꢃO distances shown by dashed lines. Thermal ellipsoids are shown at a
50% probability level.
Molecular complexes of Co(III) (2 and 3) have a typical octahe-
dral coordination of the metal atom (Figs. 3 and 4). The chelate
type coordination via nitrogen atoms of DfgHꢁ or DmgHꢁ is pres-
ent in the equatorial plane of both complexes. Two dioxime resi-
dues are combined through intramolecular OAHꢃ ꢃ ꢃO hydrogen
bonds (Oꢃ ꢃ ꢃO 2.475(3) and 2.465(3) in 2, 2.489(3) and 2.514(3),
in 3, Table 3) in a pseudomacrocyclic system. The interatomic dis-
tances CoAN (DfgH/DmgH) in complexes 2 and 3 (1.880(3)–
1.892(3) and 1.883(2)–1.918(2) Å respectively) are consistent with
those in the complexes of Co(III) (in [CoCl(DmgH)2(Inia)] [24]
CoAN 1.885(1)–1.908(1) Å). Despite the organic molecules L/L0
have several donor centers, both ligands act as monodentate neu-
tral ligands and coordinate with the metal atom by the nitrogen
atom of the pyridine fragment.
Thus, the coordination polyhedron of the central metal ion is
completed to an octahedron by nitrogen atoms of L/L0 molecules
and Brꢁ/Clꢁ anions. The interatomic distances CoAN (L/L0) signif-
icantly depend on the types of atoms which are in the trans-api-
cal position: CoAN (L/L0 1.980(3) and 1.967(2) Å in 2 and 3. In
this case, the trans-position to L in 2 is occupied by Brꢁ ion,
but in 3 the trans-position to the L0 is Clꢁ ion. These interatomic
distances are consistent with those found in dioximates of cobal-
t(III) with monodentate pyrazine (Pz), pyrazincarboxamide (Pzca)
and isonicotinamide (Co(1)AN(Pz) 1.957(2), Co(1)ACl(1)
2.2428(7) Å in [CoCl(DmgH)2(Pz)] [27]; Co(1)AN(Pzca) 1.998(3),
Co(1)ABr(1) 2.3703(6) Å in [CoBr(DfgH)2(Pzca)], Co(1)AN(Pzca)
1.968(2), Co(1)ACl(1) 2.2221(8) Å in [CoCl(NioxH)2(Pzca)] and
Fig. 2. Fragment of crystal packing in 1. The hydrogen bonds OAHꢃꢃꢃN formed zig–zag chains along the c axis (shortest intramolecular CAHꢃꢃꢃO distances are shown by dashed
lines).

280
M. Cocu et al. / Journal of Molecular Structure 1063 (2014) 274–282
Fig. 4. ORTEP drawing for 3 with a numbering scheme. Shortest intramolecular OꢃꢃꢃO distances are shown by dashed lines. Thermal ellipsoids are shown at a 50% probability
level.
Fig. 5. Fragment of crystal packing in 2. The centrosymmetric dimers formed by OAHꢃꢃꢃO hydrogen bond shown by dashed lines.
Co(1)AN(Pzca) 1.968(3), Co(1)ACl(1) 2.227(1) Å in [CoCl(DmgH)
(NioxH)(Pzca)] [28], CoAN(Inia) 1.956(1), Co(1)ACl(1) 2.2426(4)
Å in [CoIIICl(DmgH)2(Inia)] [24]).
1.341(3) Å, Table 2 and Fig. 3) and a different mode for DmgH2
and Dmg2ꢁ in
(O(3)AN(4) 1.352(3), O(4)AN(5) 1.354(3),
O(5)AN(6) 1.335(3) and O(6)AN(7) 1.336(3) Å, Table and
3
2
The oxidation state +3 of the cobalt ion in 2 and 3 is demon-
strated by CoAN and CoACl/Br bond lengths. Due to the stabiliza-
Fig. 3). In 2 and 3, the N@C and CAC interatomic distances in oxi-
mic ligands (Table 2) are characteristic of metallocycles that are
formed in a chelating coordination mode of -dioximes. These data
indicate that the composition for compound 3 is [CoCl(Dmg)
(DmgH2)(L0)], as in a similar complex with isonicotinamide [24].
A rigorous analysis of interatomic distances of trans-apical li-
gands from the cobalt and halogen atoms (Br/Cl) in 2 and 3 (Figs. 3
and 4 and Table 2) reveals the stabilization of L and L0 ligands; the
L0 in 3 is in dehydrated form of L. In the five-membered ring are the
following atom distances: N(2)AN(3) 1.404(4), N(2)AC(7) 1.502(5),
N(3)AC(9) 1.272(4), C(7)AC(8) 1.519(5) and C(8)AC(9) 1.466(5) Å
tion of charges, these two dioxime ligands coordinate in
a
bidentate mode and thus lead to the formation of a five-membered
chelate ring around the metal core, which can be stabilized both in
a monodeprotonated mode and in a different way: one is neutral,
the other is bideprotonated. The L/L0 coordinates only in a neutral
mode.
The NAO bond lengths of DfgH and DmgH ligands reveal the
monodeprotonated coordination mode of DfgH- in 2 (O(3)AN(4)
1.341(3), O(4)AN(5) 1.337(3), O(5)AN(6) 1.331(3) and O(6)AN(7)

M. Cocu et al. / Journal of Molecular Structure 1063 (2014) 274–282
281
Fig. 6. Fragment of crystal packing in 3. The chains along the crystallographic a -axis formed by CAHꢃꢃꢃCl bonds, which are linked in layers along the c-axis by the CAHꢃꢃꢃN
bonds shown by dashed lines.
in 2 and N(2)AN(3) 1.389(4), N(2)AC(7) 1.403(4), N(3)AC(9)
1.321(4), C(7)AC(8) 1.362(5) and C(8)AC(9) 1.415(4) Å in 3. The
C(6)AO(1) interatomic distances in 2 and 3 are equal to 1.224(4)
and 1. 204(4) Å, which show the double nature of this bond. The
values found for C(6)AN(2) and C(6)AC(3) (1.331(4), 1.506(5) in
2 and 1.382(4), 1.511(4) Å in 3) are slightly different. However,
4. Conclusions
The interaction of isonicotinic acid hydrazide with 2,4-pentane-
dione (enolic form) in a molar ratio of 1:1 represents a double pro-
cess of the condensation-cyclization, resulted in the formation of a
Schiff base a novel V-shaped organic ligand L which contains a five-
membered cycle with two nitrogen and three carbon atoms. In the
condensation process are involved ANH2 groups of hydrazide and
>C@O groups of 2,4-pentanedione, while in the cyclization process
– the ANH group of hydrazide and CAOH group of 2,4-pentanedi-
one fragment.
there is
a
small difference in the valence angles
N(2)C(6)C(3)A117.0(4) in 2 and 114.1(3)° in 3. The mean devia-
tions from the mean planes of the five-membered ring in 2 is
0.065 Å (the C(10) atom deviation from the mean plane is
ꢁ0.074 Å, but the O(2) and C(11) shifts ꢁ1.353 and 1.009 Å), while
in 3 the ring is almost planar, 0.003 Å (the C(10) and C(11) atoms
slightly deviate from the mean plane at 0.043 and 0.134 Å). The
torsion angles C(6)N(2)C(7)O(2) and C(6)N(2)C(7)C(11) in 2 are
64.5 and ꢁ60.2° and were similar in 1, but in 3 the angle
C(6)N(2)C(7)C(11) is ꢁ6.2°.
In cobalt(III)
dinates to the metal without chemical modification. In dim-
ethylglyoximate complex, ligand undergoes modifications,
a-benzyldioximate complex, the Schiff base L coor-
L
which can be regarded as dehydratation process on C(7)AC(8)
bond (Fig. 1), resulting in another double bond in the Schiff base
cycle with generation L0.
The dihedral angle between the pyridine and diazole rings is
49.5° in L (in 2), but the dihedral angle between these cyclic units
is 88.8° in L0 (in 3). These differences affect the crystal packing in 2
and 3.
The ligands L and L0 contain potential five and four electron do-
nor atoms, respectively, but both coordinate to the metal ion
through the nitrogen atom of the pyridine heterocycle, which
shows a higher affinity relative to examined cobalt dioximates.
In compound 2, the L ligands of two different complexes are
joined into
a
centrosymmetric dimer by the O(2)AHꢃ ꢃ ꢃO(1)
(ꢁx + 1, ꢁy + 1, ꢁz ꢁ 1) intermolecular hydrogen bonds (Table 3
and Fig. 5). In the crystal, the dimers are linked only through weak
intermolecular hydrogen-bond interactions CAHꢃ ꢃ ꢃO(oxime):
C(4)AHꢃ ꢃ ꢃO(5) (ꢁx + 1, ꢁy + 2, ꢁz) (donorꢃ ꢃ ꢃacceptor 3.190 Å),
C(2)AHꢃ ꢃ ꢃO(3) (ꢁx + 1, ꢁy + 1, ꢁz) (donorꢃ ꢃ ꢃacceptor 3.157 Å) b
C(152)AHꢃ ꢃ ꢃO(6) (ꢁx, ꢁy + 1, ꢁz) (donorꢃ ꢃ ꢃacceptor 3.352 Å).
The absence of classic donor functional groups in complex 3, ex-
cept for oxime hydroxyl groups, which are involved in the forma-
tion of intramolecular hydrogen bonds O(oxime)AHꢃ ꢃ ꢃO(oxime),
suggests that there are weak interactions of the components in
the crystal. The analysis of the possible weak interactions identi-
fied several CAHꢃ ꢃ ꢃO, CAHꢃ ꢃ ꢃN, CAHꢃ ꢃ ꢃCl hydrogen bonds, which
involve all four oxime oxygen atoms, one nitrogen atom of the pyr-
azole ring, and the coordinated chloride ion as proton acceptors:
C(10)AHꢃ ꢃ ꢃO(3) (x + 1/2, ꢁy + 3/2, z) (donorꢃ ꢃ ꢃacceptor 3.289 Å),
C(8)AHꢃ ꢃ ꢃO(4) (x + 1/2, ꢁy + 5/2, z) (donorꢃ ꢃ ꢃacceptor 3.365 Å),
C(4)AHꢃ ꢃ ꢃO(5) (x + 1/2, ꢁy + 5/2, z) (donorꢃ ꢃ ꢃacceptor 3.323 Å),
C(2)AHꢃ ꢃ ꢃO(6) (x + 1/2, ꢁy + 3/2, z) (donorꢃ ꢃ ꢃacceptor 3.341 Å),
C(12)AHꢃ ꢃ ꢃN(3) (ꢁx, ꢁy + 2, ꢁz + 1) (donorꢃ ꢃ ꢃacceptor 3.413 Å)
and C(8)AHꢃ ꢃ ꢃCl(1), (x + 1, y, z) (donorꢃ ꢃ ꢃacceptor 3.458 Å). Finally,
in crystal 3 can be identified two chains formed along the crystal-
lographic a-axis by CAHꢃ ꢃ ꢃCl bonds, which are linked in layers
along the c-axis by the CAHꢃ ꢃ ꢃN bonds (Fig. 6). The
CAHꢃ ꢃ ꢃO(oxime) hydrogen bonds are involved to connect these
layers into a 3D network.
Supplementary material
Crystallographic data for 1–3 have been deposited with the
Cambridge Crystallographic Data Center, CCDC 947227-947229.
Copies of this information may be obtained from The Director,
CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK (fax: +44-1233-
336033; e-mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
References
[1] S. Kumar, D.N. Dhar, P.N. Saxena, J. Sci. Ind. Res. (2009) 68.
[2] A. Hakim, A. Ahmed, S.A. BenGuzzi, J. Sci. Appl. 2 (1) (2008) 83.
[3] N. Brescian-Pahor, M. Farcolin, L.G. Marzilli, L. Randaccio, M.F. Summers, P.J.
Toscano, Coord. Chem. Rev. 63 (1985) 1.
[4] E.B. Coropceanu, L. Croitor, M.M. Botoshansky, M.S. Fonari, Polyhedron 30
(2011) 2592.
[5] A.A. Desyatnik, N.V. Gerbeleu, E.B. Koropchanu, Zh.P. Tyurina, S.V. Lablyuk, O.A.
Bologa, S.I. Klapko, Russ. J. Coord. Chem. 28 (2) (2002) 144.
[6] L. Croitor, E.B. Coropceanu, A.V. Siminel, V.Ch. Kravtsov, M.S. Fonari, Cryst.
Growth Des. 11 (2011) 3536.
[7] G.P. Sirtsova, Russ. J. Inorg. Chem. 19 (2) (1974) 430.
[8] Z. Otwinowski, W. Minor, Processing of X-ray diffraction data collected in
oscillation mode, in: C.W. Carter, R.M. Sweet (Eds.), Methods in Enzymology,
Macromolecular Crystallography, Part A, vol. 276, Academic Press, New York,
1997, p. 307.
[9] XEMP ver. 4.2. Siemens Analytical X-ray Inst. Inc., 1990.
[10] G.M. Sheldrick, Acta Crystallogr. 64A (2008) 112.

282
M. Cocu et al. / Journal of Molecular Structure 1063 (2014) 274–282
[11] Wei Xiong, Jiu.-Xi Chen, Miao-Chang Liu, et al., J. Braz. Chem. Soc. 20 (2) (2009)
367.
[20] C.M. Armstrong, P.V. Bernhardt, P. Chin, D.R. Richardson, Eur. J. Inorg. Chem.
(2003) 1145.
[12] F.H. Allen, O. Kennard, Chem. Des. Automation News 8 (1993) 31.
[13] H. Kargar, R. Kia, F. Froozandeh, M.H. Sadr, M.N. Tahir, Acta Crystallogr. 67E
(2011) o209.
[14] O.G. Khudina, E.V. Shchegol’kov, Y.V. Burgart, M.I. Kodess, V.I. Saloutin, O.N.
Chupakhin, Heterocycles 68 (2006) 2515.
[15] A. Nie, Z. Huang, J. Comb. Chem. 8 (2006) 655.
[16] B. Wei, Y. Gao, C.-X. Lin, H.-D. Li, Li-Li Xie, Y.-F. Yuan, J. Organomet. Chem. 696
(2011) 1574.
[21] L.A. Chugaev, Metallicheskie soedineniya
Moskwa: Izd-vo AN SSSR, T. 1, 1954, 56 p.
[22] M.M. Bishop, A.H.W. Lee, L.F. Lindoy, P. Turner, D.W. Skelton, A.H. White,
Supramol. Chem. 17 (1–2) (2005) 37.
[23] I.I. Bulhac, P.N. Bourosh, D. Schollmeyer, V.E. Zubareva, K. Suwinska, O.
Ciobanica, Yu.A. Simonov, Russ. J. Coord. Chem. 35 (5) (2009) 352.
[24] O. Chiobenike, P. Bourosh, V. Lozan, O. Bologa, I. Bulkhak, B. Wicher, Yu.
Simonov, Russ. J. Inorg. Chem. 56 (7) (2011) 1054.
a-dioximov. Izbrannye trudy.
[17] Y. Gao, H.-D. Li, Ch.-F. Ke, Li-li Xie, B. Wei, Y.-F. Yuan, Appl. Organomet. Chem.
25 (2011) 407.
[18] Di Sun, Z.-H. Wei, Ch.-F. Yang, D.-F. Yang, Na Zhang, R.-B. Huang, L.-S. Zhang,
CrystEngComm 13 (2011) 1591.
[19] G.V. Tsintsadze, Z.O. Dzhavakhishvili, G.G. Aleksandrov, Yu.T. Struchkov, A.P.
Narimanidze, Koord. Khim. (Russ.) (Coord. Chem.) 6 (1980) 785.
[25] Xu-J. Shen, Li-P. Xiao, Ru-R. Xu, Acta Crystallogr. 61E (2005) m1156.
[26] P. Du, J. Schneider, G. Luo, W.W. Brennessel, R. Eisenberg, Inorg. Chem. 48
(2009) 4952.
[27] B.D. Gupta, V. Vijaikanth, V. Singh, Organometallics 23 (2004) 2069.
[28] P. Bourosh, O. Ciobanica, V. Lozan, I. Bulhac, Russ. J. Coord. Chem. 38 (7) (2012)
461.